/*
 * File      : cpuport.c
 * This file is part of RT-Thread RTOS
 * COPYRIGHT (C) 2006 - 2014, RT-Thread Development Team
 *
 * The license and distribution terms for this file may be
 * found in the file LICENSE in this distribution or at
 * http://www.rt-thread.org/license/LICENSE
 *
 * Change Logs:
 * Date           Author       Notes
 * 2011-10-21     Bernard      the first version.
 * 2011-10-27     aozima       update for cortex-M4 FPU.
 * 2011-12-31     aozima       fixed stack align issues.
 * 2012-01-01     aozima       support context switch load/store FPU register.
 * 2012-12-11     lgnq         fixed the coding style.
 * 2012-12-23     aozima       stack addr align to 8byte.
 * 2012-12-29     Bernard      Add exception hook.
 * 2013-06-23     aozima       support lazy stack optimized.
 */

#include <rtthread.h>

#define USE_FPU   /* ARMCC */ (  (defined ( __CC_ARM ) && defined ( __TARGET_FPU_VFP )) \
                  /* IAR */   || (defined ( __ICCARM__ ) && defined ( __ARMVFP__ )) \
                  /* GNU */   || (defined ( __GNUC__ ) && defined ( __VFP_FP__ ) && !defined(__SOFTFP__)) )

/* exception and interrupt handler table */
rt_uint32_t rt_interrupt_from_thread;
rt_uint32_t rt_interrupt_to_thread;
rt_uint32_t rt_thread_switch_interrupt_flag;
/* exception hook */
static rt_err_t (*rt_exception_hook)(void* context) = RT_NULL;

struct exception_stack_frame {
	rt_uint32_t r0;
	rt_uint32_t r1;
	rt_uint32_t r2;
	rt_uint32_t r3;
	rt_uint32_t r12;
	rt_uint32_t lr;
	rt_uint32_t pc;
	rt_uint32_t psr;
};

struct stack_frame {
#if USE_FPU
	rt_uint32_t flag;
#endif /* USE_FPU */

	/* r4 ~ r11 register */
	rt_uint32_t r4;
	rt_uint32_t r5;
	rt_uint32_t r6;
	rt_uint32_t r7;
	rt_uint32_t r8;
	rt_uint32_t r9;
	rt_uint32_t r10;
	rt_uint32_t r11;

	struct exception_stack_frame exception_stack_frame;
};

struct exception_stack_frame_fpu {
	rt_uint32_t r0;
	rt_uint32_t r1;
	rt_uint32_t r2;
	rt_uint32_t r3;
	rt_uint32_t r12;
	rt_uint32_t lr;
	rt_uint32_t pc;
	rt_uint32_t psr;

#if USE_FPU
	/* FPU register */
	rt_uint32_t S0;
	rt_uint32_t S1;
	rt_uint32_t S2;
	rt_uint32_t S3;
	rt_uint32_t S4;
	rt_uint32_t S5;
	rt_uint32_t S6;
	rt_uint32_t S7;
	rt_uint32_t S8;
	rt_uint32_t S9;
	rt_uint32_t S10;
	rt_uint32_t S11;
	rt_uint32_t S12;
	rt_uint32_t S13;
	rt_uint32_t S14;
	rt_uint32_t S15;
	rt_uint32_t FPSCR;
	rt_uint32_t NO_NAME;
#endif
};

struct stack_frame_fpu {
	rt_uint32_t flag;

	/* r4 ~ r11 register */
	rt_uint32_t r4;
	rt_uint32_t r5;
	rt_uint32_t r6;
	rt_uint32_t r7;
	rt_uint32_t r8;
	rt_uint32_t r9;
	rt_uint32_t r10;
	rt_uint32_t r11;

#if USE_FPU
	/* FPU register s16 ~ s31 */
	rt_uint32_t s16;
	rt_uint32_t s17;
	rt_uint32_t s18;
	rt_uint32_t s19;
	rt_uint32_t s20;
	rt_uint32_t s21;
	rt_uint32_t s22;
	rt_uint32_t s23;
	rt_uint32_t s24;
	rt_uint32_t s25;
	rt_uint32_t s26;
	rt_uint32_t s27;
	rt_uint32_t s28;
	rt_uint32_t s29;
	rt_uint32_t s30;
	rt_uint32_t s31;
#endif

	struct exception_stack_frame_fpu exception_stack_frame;
};

rt_uint8_t* rt_hw_stack_init(void*       tentry,
                             void*       parameter,
                             rt_uint8_t* stack_addr,
                             void*       texit)
{
	struct stack_frame* stack_frame;
	rt_uint8_t*         stk;
	unsigned long       i;

	stk  = stack_addr + sizeof(rt_uint32_t);
	stk  = (rt_uint8_t*)RT_ALIGN_DOWN((rt_uint32_t)stk, 8);
	stk -= sizeof(struct stack_frame);

	stack_frame = (struct stack_frame*)stk;

	/* init all register */
	for(i = 0; i < sizeof(struct stack_frame) / sizeof(rt_uint32_t); i ++) {
		((rt_uint32_t*)stack_frame)[i] = 0xdeadbeef;
	}

	stack_frame->exception_stack_frame.r0  = (unsigned long)parameter; /* r0 : argument */
	stack_frame->exception_stack_frame.r1  = 0;                        /* r1 */
	stack_frame->exception_stack_frame.r2  = 0;                        /* r2 */
	stack_frame->exception_stack_frame.r3  = 0;                        /* r3 */
	stack_frame->exception_stack_frame.r12 = 0;                        /* r12 */
	stack_frame->exception_stack_frame.lr  = (unsigned long)texit;     /* lr */
	stack_frame->exception_stack_frame.pc  = (unsigned long)tentry;    /* entry point, pc */
	stack_frame->exception_stack_frame.psr = 0x01000000L;              /* PSR */

#if USE_FPU
	stack_frame->flag = 0;
#endif /* USE_FPU */

	/* return task's current stack address */
	return stk;
}

/**
 * This function set the hook, which is invoked on fault exception handling.
 *
 * @param exception_handle the exception handling hook function.
 */
void rt_hw_exception_install(rt_err_t (*exception_handle)(void* context))
{
	rt_exception_hook = exception_handle;
}

void rt_hw_hard_fault_exception(struct exception_stack_frame* exception_stack)
{
	extern long list_thread(void);

	if(rt_exception_hook != RT_NULL) {
		rt_err_t result;

		result = rt_exception_hook(exception_stack);

		if(result == RT_EOK) return;
	}

	rt_kprintf("psr: 0x%08x\n", exception_stack->psr);
	rt_kprintf(" pc: 0x%08x\n", exception_stack->pc);
	rt_kprintf(" lr: 0x%08x\n", exception_stack->lr);
	rt_kprintf("r12: 0x%08x\n", exception_stack->r12);
	rt_kprintf("r03: 0x%08x\n", exception_stack->r3);
	rt_kprintf("r02: 0x%08x\n", exception_stack->r2);
	rt_kprintf("r01: 0x%08x\n", exception_stack->r1);
	rt_kprintf("r00: 0x%08x\n", exception_stack->r0);

	rt_kprintf("hard fault on thread: %s\n", rt_thread_self()->name);

#ifdef RT_USING_FINSH
	list_thread();
#endif

	while(1);
}

/**
 * shutdown CPU
 */
void rt_hw_cpu_shutdown(void)
{
	rt_kprintf("shutdown...\n");

	RT_ASSERT(0);
}

#ifdef RT_USING_CPU_FFS
/**
 * This function finds the first bit set (beginning with the least significant bit)
 * in value and return the index of that bit.
 *
 * Bits are numbered starting at 1 (the least significant bit).  A return value of
 * zero from any of these functions means that the argument was zero.
 *
 * @return return the index of the first bit set. If value is 0, then this function
 * shall return 0.
 */
#if defined(__CC_ARM)
__asm int __rt_ffs(int value)
{
	CMP     r0, #0x00
	BEQ     exit

	RBIT    r0, r0
	CLZ     r0, r0
	ADDS    r0, r0, #0x01

	exit
	BX      lr
}
#elif defined(__IAR_SYSTEMS_ICC__)
int __rt_ffs(int value)
{
	if(value == 0) return value;

	asm("RBIT %0, %1" : "=r"(value) : "r"(value));
	asm("CLZ  %0, %1" : "=r"(value) : "r"(value));
	asm("ADDS %0, %1, #0x01" : "=r"(value) : "r"(value));

	return value;
}
#elif defined(__GNUC__)
int __rt_ffs(int value)
{
	return __builtin_ffs(value);
}
#endif

#endif
